Systems that are secured for use only by authorized individuals frequently rely upon a password or personal identification number (PIN). Examples of systems which utilize PINs include college registration, employee access to information, cellular phones and other communication devices in addition to savings and checking accounts, ATM transactions, telephone calling cards, debit cards, credit cards and numerous other systems.
While some individuals are able to remember random sequences of numbers and letters, most passwords and PINs are selected by the individual to have some personal relevance so that they can be easily remembered. Frequently, words and number combinations that relate to loved ones, pets, colleagues, birthdays, telephone numbers, addresses and social security numbers are used for passwords and PINs. Such associations provide hackers, thieves, spies and others with weaknesses that they can exploit in order to gain unauthorized access. Even when random words and numbers are used, they are frequently written in a list that is kept handy. The list of passwords and PINs is often not well secured itself, which also facilitates unauthorized access.
Individuals are faced with the dilemma of having a password or PIN that is easy to remember and consequently facilitates unauthorized access or having a password or PIN that is so difficult to remember that it may have to be written down, thus negating the added security.